Air entering a turbine compressor inlet and similar devices should be filtered before compression or other use. Impure inlet air laden with dirt, debris, dust particles, salt, and other contaminants may damage the compressor blades, plug cooling passages, and damage other types of power generation equipment via corrosion, erosion, fouling, and the like. Such damage may reduce the life expectancy and the overall performance of the generation equipment. To avoid this problem, the inlet air may pass through one or more filters to remove the contaminants.
The air filters, however, may have a relatively short life span due to accumulation of the dirt, debris, and other types of contaminants. This accumulation also may raise the pressure drop across the filter element. Raising the pressure drop reduces the overall power output and the efficiency of the gas turbine engine. As such, the filter elements typically may be replaced when the pressure drop reaches the point in which the gas turbine operator deems the loss of machine efficiency exceeds the costs of the replacing the filters. Many gas turbine engines may have automatic controls that signal when the filters have reach a predetermined set point and that filter replacement is needed. If the operator does not replace the filters at the alarm point, additional controls may shut the gas turbine engine down to prevent inlet or filter implosion due to high filter element pressure drops. The gas turbine engine typically may be shutdown for the replacement of the filters.
Frequent filter replacement thus may result in high maintenance costs to the gas turbine end user in terms of labor and filters as well as the loss of revenue due to engine downtime and unavailability. Likewise, online replacement of the filters may result in premature wear of the gas turbine internal components.
To date, known self-cleaning inlet air filter elements have relied on a reverse blast of compressed air that creates a shock wave which knocks off the accumulated dirt, debris, and other contaminants off of the filter elements. The dirt and debris located at the top of the filter elements, however, may accumulate and may not be effectively cleaned by the compressed air self cleaning.
There is thus a desire for an improved inlet air filtering systems. Such systems preferably can avoid the accumulation of dirt, debris, and other contaminants without an increased pressure drop therethrough. Overall system efficiency and performance also should be improved.